Proximity sensors typically comprise a radiation source and a corresponding detector, the detector comprising a relatively small number of exposed radiation sensitive pixels (from a single pixel up to, for example, a 10×10 pixel array). At its simplest the proximity sensor is capable of indicating the presence or absence of a user or object. Additional computation and circuit complexity can provide enhanced data such as the range to an object.
Proximity sensing is achieved by: emitting radiation from the source; capturing radiation which is reflected back to the detector by an object; and processing the reflected radiation to determine the proximity of the object to the sensor. Proximity sensors are used in many applications, including on mobile communications devices and vehicle parking sensors.
The source and the detector of existing proximity sensors are typically provided in separate packages with separate control circuitry. However, it is desirable to reduce their size and complexity.